This invention relates to drip irrigation hose and more particularly to a drip irrigation hose having self-cleaning inlets and a method for manufacturing such a hose.
U.S. Pat. No. 5,123,984 to Allport et al. discloses a drip irrigation hose made from an elongated strip of plastic film folded longitudinally to form overlapping longitudinal margins. Molded plastic beads seal the overlapping margins and form a flow regulating channel for water exiting the drip irrigation hose. The characteristics of the flow regulating channel, the inlets to the channel, and/or the outlets from the channel are determined by the pattern on a molding wheel that shapes a bead extruded on one margin of the film.
In a prior art design disclosed in U.S. Pat. No. 5,003,726 to Allport the flow regulating channel is formed by a pair of parallel rib forming beads in the overlapping margins. Inlets to the flow regulating channel are formed by interruptions in the inboard bead. Outlets from the hose are formed in the outboard bead or the film itself. There is a tenancy in some soil conditions for the inlets to become plugged as debris in the water builds up at the entrance to the flow regulating channel, which reduces the drip flow rate through the portion of the flow regulating channel fed by the plugged inlets.